Quoted from Rarehero:
People always say this, but it's always wrong. They always have a portfolio of games in production at any given time. Every game has the possibility of being in production for 3 years. New titles don't "hurt" previous titles...previous titles don't hurt new titles. They're ALL for sale, they all have an audience.
Edit: Just looked on their website...they currently have TEN titles in production!!!! That's an amazing amount of choice for potential customers. There's something for everyone.
Stern's line can run multiple titles, which allows them to do this.
If memory serves, that wasn't the case for Williams. They did one title at a time, trying to estimate sales. That's why they never wanted the next title to leak, which would hurt sales of the current. Someone with better knowledge of Williams should probably chime in here if my statement is all wrong
Anyway, that's why I agree with you that the next title won't hurt GB sales. It's a different market now with 10 titles in production. Truly amazing!